1. Field of the Invention
This invention relates generally to shipping containers and more particularly a container adapted for shipping medically useful rodents in an environment that insures maximum animal survival and facilitates animal loading and removal.
2. Prior Art
Containers particularly adapted for shipping small animals such as young poultry chicks, mice, or rats have been known and in use for many years.
One early example of this type of container is disclosed in U.S. Pat. No. 1,236,918. This container is a paper board receptacle that includes an open top box divided into compartments by interior partitions. The open top of the box is closed by a cover having a down-turned outer edge that fits tightly about a top peripheral edge of side and end walls of the box. In a top wall of the cover are four triangular-shaped vent opening sets. These opening sets may be selectively covered by a damper plate pivotally carried on the cover below a middle cross member. The cross member is located between spaced apart end members fastened next to respective ends of the cover. Fitted to the end and cross members is a set of three spaced apart longitudinal strips. Ends of the longitudinal strips and end members extend beyond the cover sides and ends.
During use, the outward extending ends of the cover end members and cross members prevent close-packing of a receptacle with adjacent shipping containers. Additionally, these members provide a space for air to circulate to the cover openings.
A further shipping container for laboratory animals is set out in U.S. Pat. No. 4,976,219. This container comprises a bottom plastic tray enclosed by a permanently attached dome-shaped perforated cover. An opening in a middle of a top wall of the cover provides access to an interior of the container. A retaining seal is permanently pressed into the cover opening to hold a removable wire mesh retainer and a transparent cover permanently attached to the retainer. Protrusions on the tray enhance stacking by maintaining registry between the cover of a lower container with the bottom tray of an above container.
A still further container for transporting laboratory animals is disclosed in U.S. Pat. No. 5,370,079. This container includes a base preferably made from wax-coated material. Sidewalls and end walls of the base slant upward and inward from a bottom to connect with an upper, outward projecting peripheral flange. The base walls are formed with vent openings lined with an air permeable material and then covered with wire mesh. The base is enclosed by a lid divided into first and second end portions by a fold line. Foldable edge tabs on the first lid portion are affixed to aligned portions of the base top flange by adhesive, for example. The tabs of the second lid portion and remaining base top flange portions then are joined by a single thread chain stitch. To open the container, an unstitched end of the thread is pulled to release the lid second portion. During transit, the slanted sides of the base insure that air flows to the vent openings.
A more recent animal tote is set out in U.S. Pat. No. 5,572,953. This tote comprises a bottom container portion having outwardly sloped sidewalls and end walls. In the sidewalls are recessed areas formed with respective sets of minute holes. Upper ends of the container walls connect with a top horizontal peripheral flange. This container flange fits into a channel formed by a spaced apart, inner and outer downwardly facing flanges formed about a periphery of a lid of the tote. A set of snaps in the lid outer flange secures the lid to the container. In each corner of the lid top member is a post having a flanged receiving area to hold a respective bottom corner of an above stacked tote container portion. These posts maintain a set of stacked totes in a spaced apart relationship allowing air to circulate to the lid holes. Lastly, like the container sidewalls, the lip top member has a set of recessed areas of minute holes. In each case, filter frames fit in the recess areas where side edges of the frames are held in place by shoulders on sides of the recesses.
A container of this invention is particularly adapted for shipping rodents or other like animals used in medical experiments, for example. This container includes a boxlike shaped base defined by a bottom wall and connecting outwardly sloped side and end walls formed with openings. Upper ends of the base walls connect with a peripheral edge flange. Sealed in each base opening is a removable filter unit. Each filter unit comprises a support member having a raised edge fitting about a perforated backing plate. The raised edge is formed with an outward facing channel that fits over an edge of the opening. Covering an outer side of the unit backing plate is a piece of filter cloth. This cloth piece then is held in place by a retainer having an open structure surrounded by a peripheral edge segment that fits under a set of spaced apart tabs on an inside of the support member raised edge. These tabs align with slots in the support member backing plate and facilitate placement of and removal of the retainer edge segment from under these tabs.
An interior space of the container base may be divided into two large compartments by a lateral partition having outer edges securable between ribs on an inner side of each base sidewall. This partition includes a feeding bin accessible from each compartment. These two large compartments then are further dividable into small compartments by longitudinal partitions.
The container base is enclosed by a lid. A middle cross piece of the lid has end down-turned edge channels with snaps that fit over respective opposing sections of the base sidewall edge flange. Integrally hinged to each side of the lid middle cross piece is an outer section having respective edge channels with like snaps to engage adjacent sections of the base edge flange. With all lid snaps engaged, the lid forms an airtight fit with the base. In a middle of each lid outer section is a raised portion defined by upwardly sloped end walls having pairs of openings for further filter units. Upper ends of these sloped end walls connect with a top horizontal segment having posts located on respective sides of a set of integrally formed transparent windows.
For use, the interior space of the base is selectively divided into compartments by the partitions for ready placement of rodents. As each large compartment of the container is filled, the outer section of the lid for that compartment is closed. When loading is complete, a set of containers may be vertically stacked by placing inverted, cup-shaped openings in a base bottom wall of an above container over the lid posts of a below container. As stacked and then closely packed, the filter units of each container remain free for in-and-out movement of fresh, filtered air.
The container of this invention provides several advantages over containers now known or presently in use.
A first advantage is that movement of air into and from the container is restricted to that which flows through the filter cloth of each filter unit. Note that the lid and base are joined by a releasable, but airtight connection. Additionally, each filter unit backing plate raised edge forms an airtight fit with its respective opening in the lid and base. Thus, rodents in a container remain isolated from ambient bacteria or viruses outside the container, and any like airborne contaminants. remain in the container.
Secondly, the positioning of the base filter units and the lid filter units insure cross-ventilation of the container. In particular, the eight filter units in the container lid provide more than adequate surface area for venting heat generated by the encased animals. Further, were a particular side of the base or portion of the lid inadvertently covered, there is a sufficient number of other filter units to insure that filtered air circulates to the encased animals.
Another important advantage is that the container may be readily sterilized after each shipment. Sterilization is critical to inhibit a possibility of cross-contamination from one shipment. to the next. Since the base, lid and filter unit support members and retainer are made of a rigid; high temperature thermosetting plastic, e.g., polypropylene, interior surfaces may be subjected to scouring at sterilizing temperatures. This required clearing is facilitated by ready disassembly of the lid from the base, the filter units from the container, and removal of the lateral partition from the base. Additionally, the filter unit retainer can be readily separated from its respective support member to provide access to the filter cloth. Were a container to be damaged requiring the container to be scrapped, the container is made recyclable material.
Finally, excluding the interior partitions and pieces of filter cloth, this container comprises just four individual moldable components. Interior partitioning adds two additional components. Requiring only six individual parts minimizes tooling costs while piece costs remain competitive.